Television Bus Manipulator

This is a device that can be installed into CRT television to modify the data sent to its video/colour processor over the I2C bus. It may be useful to enable Fast Blanking (RGB input enable pin) or other features of the video/colour processor which are disabled by the television's microcontroller.

This project currently supports the Philips TDA8366 and TDA837x family. It switches on the IE1 bit of register 0x11 (saturation). If could easily be modified to suit other processors and registers by changing the required values in the source near the top of main.c.

The target hardware is the Cypress PSOC 4 Development board - CY8CKIT-049-42XX.

To program the hardware a programmer is required. The Cypress Miniprog 3 can be used, but it's quite expensive to buy. I recommend the programmer that comes with the Cypress PSOC 5LP Development board - CY8CKIT-059 (I probably should have targeted this board to begin with) called the Kitprog.


  1. Remove the USB to serial part of the CY8CKIT-049-42XX. (optional)
  2. Make changes to the source as necessary. (optional)
  3. Compile the source with PSOC Creator 3.3 or later version. (optional)
  4. Program the CY8CKIT-049-42XX with either a Cypress Miniprog 3 or Kitprog programmer. The software for driving the programmer can be either PSOC Creator 3.3 (or later version) or PSOC Programmer. The latter is easier to use.
  5. Install the CY8CKIT-049-42XX into the television set, following the installation diagram. The SDA and SCL pins of the video processor should be isolated and connected to the MASTER_SDA and MASTER_SCL pins. Sometimes there are convenient resistors in series with these pins on the television board. Sometimes cutting the the PCB trace is the only way. A pair of external pull up resistors is required. The SDA and SCL pins of the bus should be connected to SLAVE_SDA and SLAVE_SCL. A source of 5V power is required. The easiest way to find 5V power is to look for the microcontroller's EEPROM, in a 8 pin DIP package. Pin 4 is ground, pin 8 is +5V.

Note regarding in circuit programming

I recommend disconnecting the CY8CKIT-049-42XX from television chassis if you want to reprogram it. If you insist on programming in circuit, remember to connect the television ground to earth (known as safety ground in America) before connecting the programmer. Also remember that the communication between the television's microcontroller and the video/colour processor will stop while the CY8CKIT-049-42XX hardware is being programmed.


Television Bus Manipulator software (source and binary). Project for PSOC Creator 3.3.

Installation diagram.

Data sheet for TDA837x family.

Data sheet for TDA8366.

PSOC Creator and PSOC Programmer.

Last modified 13/11/2017.